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In strict mode, raise `NotADirectoryError` if we encounter a non-directory while we still have path parts left to process. We use a `part_count` variable rather than `len(rest)` because the `rest` stack also contains markers for unresolved symlinks.
587 lines
18 KiB
Python
587 lines
18 KiB
Python
"""Common operations on Posix pathnames.
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Instead of importing this module directly, import os and refer to
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this module as os.path. The "os.path" name is an alias for this
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module on Posix systems; on other systems (e.g. Windows),
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os.path provides the same operations in a manner specific to that
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platform, and is an alias to another module (e.g. ntpath).
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Some of this can actually be useful on non-Posix systems too, e.g.
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for manipulation of the pathname component of URLs.
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"""
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# Strings representing various path-related bits and pieces.
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# These are primarily for export; internally, they are hardcoded.
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# Should be set before imports for resolving cyclic dependency.
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curdir = '.'
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pardir = '..'
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extsep = '.'
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sep = '/'
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pathsep = ':'
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defpath = '/bin:/usr/bin'
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altsep = None
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devnull = '/dev/null'
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import errno
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import os
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import sys
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import stat
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import genericpath
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from genericpath import *
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__all__ = ["normcase","isabs","join","splitdrive","splitroot","split","splitext",
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"basename","dirname","commonprefix","getsize","getmtime",
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"getatime","getctime","islink","exists","lexists","isdir","isfile",
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"ismount", "expanduser","expandvars","normpath","abspath",
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"samefile","sameopenfile","samestat",
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"curdir","pardir","sep","pathsep","defpath","altsep","extsep",
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"devnull","realpath","supports_unicode_filenames","relpath",
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"commonpath", "isjunction","isdevdrive"]
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def _get_sep(path):
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if isinstance(path, bytes):
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return b'/'
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else:
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return '/'
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# Normalize the case of a pathname. Trivial in Posix, string.lower on Mac.
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# On MS-DOS this may also turn slashes into backslashes; however, other
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# normalizations (such as optimizing '../' away) are not allowed
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# (another function should be defined to do that).
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def normcase(s):
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"""Normalize case of pathname. Has no effect under Posix"""
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return os.fspath(s)
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# Return whether a path is absolute.
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# Trivial in Posix, harder on the Mac or MS-DOS.
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def isabs(s):
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"""Test whether a path is absolute"""
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s = os.fspath(s)
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sep = _get_sep(s)
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return s.startswith(sep)
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# Join pathnames.
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# Ignore the previous parts if a part is absolute.
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# Insert a '/' unless the first part is empty or already ends in '/'.
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def join(a, *p):
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"""Join two or more pathname components, inserting '/' as needed.
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If any component is an absolute path, all previous path components
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will be discarded. An empty last part will result in a path that
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ends with a separator."""
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a = os.fspath(a)
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sep = _get_sep(a)
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path = a
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try:
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for b in p:
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b = os.fspath(b)
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if b.startswith(sep) or not path:
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path = b
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elif path.endswith(sep):
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path += b
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else:
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path += sep + b
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except (TypeError, AttributeError, BytesWarning):
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genericpath._check_arg_types('join', a, *p)
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raise
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return path
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# Split a path in head (everything up to the last '/') and tail (the
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# rest). If the path ends in '/', tail will be empty. If there is no
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# '/' in the path, head will be empty.
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# Trailing '/'es are stripped from head unless it is the root.
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def split(p):
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"""Split a pathname. Returns tuple "(head, tail)" where "tail" is
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everything after the final slash. Either part may be empty."""
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p = os.fspath(p)
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sep = _get_sep(p)
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i = p.rfind(sep) + 1
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head, tail = p[:i], p[i:]
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if head and head != sep*len(head):
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head = head.rstrip(sep)
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return head, tail
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# Split a path in root and extension.
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# The extension is everything starting at the last dot in the last
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# pathname component; the root is everything before that.
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# It is always true that root + ext == p.
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def splitext(p):
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p = os.fspath(p)
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if isinstance(p, bytes):
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sep = b'/'
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extsep = b'.'
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else:
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sep = '/'
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extsep = '.'
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return genericpath._splitext(p, sep, None, extsep)
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splitext.__doc__ = genericpath._splitext.__doc__
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# Split a pathname into a drive specification and the rest of the
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# path. Useful on DOS/Windows/NT; on Unix, the drive is always empty.
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def splitdrive(p):
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"""Split a pathname into drive and path. On Posix, drive is always
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empty."""
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p = os.fspath(p)
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return p[:0], p
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try:
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from posix import _path_splitroot_ex as splitroot
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except ImportError:
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def splitroot(p):
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"""Split a pathname into drive, root and tail.
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The tail contains anything after the root."""
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p = os.fspath(p)
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if isinstance(p, bytes):
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sep = b'/'
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empty = b''
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else:
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sep = '/'
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empty = ''
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if p[:1] != sep:
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# Relative path, e.g.: 'foo'
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return empty, empty, p
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elif p[1:2] != sep or p[2:3] == sep:
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# Absolute path, e.g.: '/foo', '///foo', '////foo', etc.
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return empty, sep, p[1:]
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else:
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# Precisely two leading slashes, e.g.: '//foo'. Implementation defined per POSIX, see
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# https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13
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return empty, p[:2], p[2:]
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# Return the tail (basename) part of a path, same as split(path)[1].
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def basename(p):
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"""Returns the final component of a pathname"""
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p = os.fspath(p)
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sep = _get_sep(p)
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i = p.rfind(sep) + 1
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return p[i:]
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# Return the head (dirname) part of a path, same as split(path)[0].
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def dirname(p):
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"""Returns the directory component of a pathname"""
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p = os.fspath(p)
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sep = _get_sep(p)
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i = p.rfind(sep) + 1
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head = p[:i]
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if head and head != sep*len(head):
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head = head.rstrip(sep)
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return head
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# Is a path a mount point?
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# (Does this work for all UNIXes? Is it even guaranteed to work by Posix?)
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def ismount(path):
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"""Test whether a path is a mount point"""
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try:
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s1 = os.lstat(path)
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except (OSError, ValueError):
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# It doesn't exist -- so not a mount point. :-)
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return False
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else:
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# A symlink can never be a mount point
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if stat.S_ISLNK(s1.st_mode):
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return False
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path = os.fspath(path)
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if isinstance(path, bytes):
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parent = join(path, b'..')
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else:
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parent = join(path, '..')
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try:
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s2 = os.lstat(parent)
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except OSError:
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parent = realpath(parent)
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try:
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s2 = os.lstat(parent)
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except OSError:
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return False
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# path/.. on a different device as path or the same i-node as path
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return s1.st_dev != s2.st_dev or s1.st_ino == s2.st_ino
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# Expand paths beginning with '~' or '~user'.
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# '~' means $HOME; '~user' means that user's home directory.
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# If the path doesn't begin with '~', or if the user or $HOME is unknown,
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# the path is returned unchanged (leaving error reporting to whatever
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# function is called with the expanded path as argument).
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# See also module 'glob' for expansion of *, ? and [...] in pathnames.
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# (A function should also be defined to do full *sh-style environment
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# variable expansion.)
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def expanduser(path):
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"""Expand ~ and ~user constructions. If user or $HOME is unknown,
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do nothing."""
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path = os.fspath(path)
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if isinstance(path, bytes):
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tilde = b'~'
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else:
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tilde = '~'
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if not path.startswith(tilde):
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return path
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sep = _get_sep(path)
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i = path.find(sep, 1)
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if i < 0:
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i = len(path)
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if i == 1:
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if 'HOME' not in os.environ:
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try:
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import pwd
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except ImportError:
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# pwd module unavailable, return path unchanged
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return path
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try:
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userhome = pwd.getpwuid(os.getuid()).pw_dir
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except KeyError:
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# bpo-10496: if the current user identifier doesn't exist in the
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# password database, return the path unchanged
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return path
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else:
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userhome = os.environ['HOME']
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else:
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try:
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import pwd
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except ImportError:
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# pwd module unavailable, return path unchanged
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return path
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name = path[1:i]
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if isinstance(name, bytes):
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name = os.fsdecode(name)
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try:
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pwent = pwd.getpwnam(name)
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except KeyError:
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# bpo-10496: if the user name from the path doesn't exist in the
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# password database, return the path unchanged
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return path
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userhome = pwent.pw_dir
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# if no user home, return the path unchanged on VxWorks
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if userhome is None and sys.platform == "vxworks":
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return path
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if isinstance(path, bytes):
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userhome = os.fsencode(userhome)
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userhome = userhome.rstrip(sep)
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return (userhome + path[i:]) or sep
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# Expand paths containing shell variable substitutions.
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# This expands the forms $variable and ${variable} only.
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# Non-existent variables are left unchanged.
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_varprog = None
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_varprogb = None
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def expandvars(path):
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"""Expand shell variables of form $var and ${var}. Unknown variables
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are left unchanged."""
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path = os.fspath(path)
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global _varprog, _varprogb
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if isinstance(path, bytes):
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if b'$' not in path:
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return path
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if not _varprogb:
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import re
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_varprogb = re.compile(br'\$(\w+|\{[^}]*\})', re.ASCII)
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search = _varprogb.search
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start = b'{'
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end = b'}'
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environ = getattr(os, 'environb', None)
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else:
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if '$' not in path:
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return path
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if not _varprog:
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import re
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_varprog = re.compile(r'\$(\w+|\{[^}]*\})', re.ASCII)
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search = _varprog.search
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start = '{'
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end = '}'
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environ = os.environ
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i = 0
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while True:
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m = search(path, i)
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if not m:
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break
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i, j = m.span(0)
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name = m.group(1)
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if name.startswith(start) and name.endswith(end):
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name = name[1:-1]
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try:
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if environ is None:
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value = os.fsencode(os.environ[os.fsdecode(name)])
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else:
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value = environ[name]
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except KeyError:
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i = j
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else:
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tail = path[j:]
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path = path[:i] + value
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i = len(path)
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path += tail
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return path
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# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.
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# It should be understood that this may change the meaning of the path
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# if it contains symbolic links!
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try:
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from posix import _path_normpath as normpath
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except ImportError:
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def normpath(path):
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"""Normalize path, eliminating double slashes, etc."""
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path = os.fspath(path)
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if isinstance(path, bytes):
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sep = b'/'
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dot = b'.'
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dotdot = b'..'
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else:
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sep = '/'
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dot = '.'
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dotdot = '..'
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if not path:
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return dot
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_, initial_slashes, path = splitroot(path)
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comps = path.split(sep)
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new_comps = []
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for comp in comps:
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if not comp or comp == dot:
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continue
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if (comp != dotdot or (not initial_slashes and not new_comps) or
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(new_comps and new_comps[-1] == dotdot)):
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new_comps.append(comp)
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elif new_comps:
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new_comps.pop()
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comps = new_comps
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path = initial_slashes + sep.join(comps)
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return path or dot
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def abspath(path):
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"""Return an absolute path."""
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path = os.fspath(path)
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if isinstance(path, bytes):
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if not path.startswith(b'/'):
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path = join(os.getcwdb(), path)
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else:
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if not path.startswith('/'):
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path = join(os.getcwd(), path)
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return normpath(path)
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# Return a canonical path (i.e. the absolute location of a file on the
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# filesystem).
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def realpath(filename, *, strict=False):
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"""Return the canonical path of the specified filename, eliminating any
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symbolic links encountered in the path."""
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filename = os.fspath(filename)
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if isinstance(filename, bytes):
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sep = b'/'
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curdir = b'.'
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pardir = b'..'
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getcwd = os.getcwdb
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else:
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sep = '/'
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curdir = '.'
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pardir = '..'
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getcwd = os.getcwd
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return _realpath(filename, strict, sep, curdir, pardir, getcwd)
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def _realpath(filename, strict=False, sep=sep, curdir=curdir, pardir=pardir,
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getcwd=os.getcwd, lstat=os.lstat, readlink=os.readlink, maxlinks=None):
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# The stack of unresolved path parts. When popped, a special value of None
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# indicates that a symlink target has been resolved, and that the original
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# symlink path can be retrieved by popping again. The [::-1] slice is a
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# very fast way of spelling list(reversed(...)).
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rest = filename.split(sep)[::-1]
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# Number of unprocessed parts in 'rest'. This can differ from len(rest)
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# later, because 'rest' might contain markers for unresolved symlinks.
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part_count = len(rest)
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# The resolved path, which is absolute throughout this function.
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# Note: getcwd() returns a normalized and symlink-free path.
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path = sep if filename.startswith(sep) else getcwd()
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# Mapping from symlink paths to *fully resolved* symlink targets. If a
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# symlink is encountered but not yet resolved, the value is None. This is
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# used both to detect symlink loops and to speed up repeated traversals of
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# the same links.
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seen = {}
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# Number of symlinks traversed. When the number of traversals is limited
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# by *maxlinks*, this is used instead of *seen* to detect symlink loops.
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link_count = 0
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while part_count:
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name = rest.pop()
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if name is None:
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# resolved symlink target
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seen[rest.pop()] = path
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continue
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part_count -= 1
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if not name or name == curdir:
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# current dir
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continue
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if name == pardir:
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# parent dir
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path = path[:path.rindex(sep)] or sep
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continue
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if path == sep:
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newpath = path + name
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else:
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newpath = path + sep + name
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try:
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st_mode = lstat(newpath).st_mode
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if not stat.S_ISLNK(st_mode):
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if strict and part_count and not stat.S_ISDIR(st_mode):
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raise OSError(errno.ENOTDIR, os.strerror(errno.ENOTDIR),
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newpath)
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path = newpath
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continue
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elif maxlinks is not None:
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link_count += 1
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if link_count > maxlinks:
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if strict:
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raise OSError(errno.ELOOP, os.strerror(errno.ELOOP),
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newpath)
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path = newpath
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continue
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elif newpath in seen:
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# Already seen this path
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path = seen[newpath]
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if path is not None:
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# use cached value
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continue
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# The symlink is not resolved, so we must have a symlink loop.
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if strict:
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raise OSError(errno.ELOOP, os.strerror(errno.ELOOP),
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newpath)
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path = newpath
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continue
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target = readlink(newpath)
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except OSError:
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if strict:
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raise
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path = newpath
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continue
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# Resolve the symbolic link
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if target.startswith(sep):
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# Symlink target is absolute; reset resolved path.
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path = sep
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if maxlinks is None:
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# Mark this symlink as seen but not fully resolved.
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seen[newpath] = None
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# Push the symlink path onto the stack, and signal its specialness
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# by also pushing None. When these entries are popped, we'll
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# record the fully-resolved symlink target in the 'seen' mapping.
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rest.append(newpath)
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rest.append(None)
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# Push the unresolved symlink target parts onto the stack.
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target_parts = target.split(sep)[::-1]
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rest.extend(target_parts)
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part_count += len(target_parts)
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return path
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supports_unicode_filenames = (sys.platform == 'darwin')
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def relpath(path, start=None):
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"""Return a relative version of a path"""
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path = os.fspath(path)
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if not path:
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raise ValueError("no path specified")
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if isinstance(path, bytes):
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curdir = b'.'
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sep = b'/'
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pardir = b'..'
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else:
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curdir = '.'
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sep = '/'
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pardir = '..'
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|
|
|
if start is None:
|
|
start = curdir
|
|
else:
|
|
start = os.fspath(start)
|
|
|
|
try:
|
|
start_tail = abspath(start).lstrip(sep)
|
|
path_tail = abspath(path).lstrip(sep)
|
|
start_list = start_tail.split(sep) if start_tail else []
|
|
path_list = path_tail.split(sep) if path_tail else []
|
|
# Work out how much of the filepath is shared by start and path.
|
|
i = len(commonprefix([start_list, path_list]))
|
|
|
|
rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
|
|
if not rel_list:
|
|
return curdir
|
|
return sep.join(rel_list)
|
|
except (TypeError, AttributeError, BytesWarning, DeprecationWarning):
|
|
genericpath._check_arg_types('relpath', path, start)
|
|
raise
|
|
|
|
|
|
# Return the longest common sub-path of the sequence of paths given as input.
|
|
# The paths are not normalized before comparing them (this is the
|
|
# responsibility of the caller). Any trailing separator is stripped from the
|
|
# returned path.
|
|
|
|
def commonpath(paths):
|
|
"""Given a sequence of path names, returns the longest common sub-path."""
|
|
|
|
paths = tuple(map(os.fspath, paths))
|
|
|
|
if not paths:
|
|
raise ValueError('commonpath() arg is an empty sequence')
|
|
|
|
if isinstance(paths[0], bytes):
|
|
sep = b'/'
|
|
curdir = b'.'
|
|
else:
|
|
sep = '/'
|
|
curdir = '.'
|
|
|
|
try:
|
|
split_paths = [path.split(sep) for path in paths]
|
|
|
|
try:
|
|
isabs, = {p.startswith(sep) for p in paths}
|
|
except ValueError:
|
|
raise ValueError("Can't mix absolute and relative paths") from None
|
|
|
|
split_paths = [[c for c in s if c and c != curdir] for s in split_paths]
|
|
s1 = min(split_paths)
|
|
s2 = max(split_paths)
|
|
common = s1
|
|
for i, c in enumerate(s1):
|
|
if c != s2[i]:
|
|
common = s1[:i]
|
|
break
|
|
|
|
prefix = sep if isabs else sep[:0]
|
|
return prefix + sep.join(common)
|
|
except (TypeError, AttributeError):
|
|
genericpath._check_arg_types('commonpath', *paths)
|
|
raise
|